SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a7a1964478b68b46ad59c5f5549c3625aeb70b30bfbaa12938349579733646d' 
  AND token = '+dDfOj3Yl/tW+8gDghuNnEDPE5NL1L7SwyvBWdQVihk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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