SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dcc6b2ae402cf9a9ed3c912c2c82c2a5cc329edcb99159d79da48ca8c436de29' 
  AND token = '6MRrKP6QHmwweM5oWISFqplscLtHGyuMLT6b/RyqVoE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.01020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}