SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a4c344c17bdb70fdb18049637fc1f1622b12f4548c97eb253714d470fc590a8' 
  AND token = 'yO0OmGH9SNNPPVPsfZEnqRnx3hD9zgIiDLGlSgGUVjM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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