SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b61b90386705f9835ea2cca386532a4798ba565279eef17e3fc34c022bff480d' 
  AND token = '0wPYWCU2gNDKWqkb7/4mvtx2GmFNpJW5bxnp4QvaBv4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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