SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75c7840e760a0b92364d108426708add63aff624c151e93586ed561e804ac806' 
  AND token = 'tL3X2nSOGxbN0kWx1CpkjcyQ7xCBz/2WFQO9Y+iRbD0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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