SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4caae8f52143c73f6d94ee22c3610808163711a93075560d44903977bf3a718' 
  AND token = 'cEoJEtA+Pa68XTsDhcb6ygWjuYE1saSYXFHftNYPHmE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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