SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6defbc7a2c163b203537a589580555a5411fa33466eb942856a7208474017f0' 
  AND token = 'MX1Uo3JR8gXbODB5RzxnSQPF0mG/m7TF850p9MmlXts=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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