SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e64a45828f38216a29fd39fa37295d617bae1420915e55167bec7f0b6bf2c9c5' 
  AND token = 'LF3y1dS3fhQL52DZORWgUkhD/48Fg0qGYklBb5GUkY8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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