SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '3df0e614538fe32f23723ca94c360e362cdd3e497b499ae85292272b21173d5a' 
  AND token = 'VZ5W/KYbGP1eA+xYPub6sncMG12h2u7qVcSqv4NjcQY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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