SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '390906b956aa391cfd147fca7d6ebb209942ce98f1298aaad80d40351ca24973' 
  AND token = 'Pe7F4SFYhltkfEMpC47l5Do5j4GyCZ3T1VQQfIwA7kk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}