SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eab49a60491df504257faa334efd20891020b650ca56474f8c7635b2b7e8019a' 
  AND token = 'PgKnGLIxYfo4usTJCvvNlogp2Ni6+tzYl7s4XkANjF0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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