SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7804e95362b49660c496e7389e4462985cad9267eb54499e8216a6776b9fb62b' 
  AND token = 'uRgo/ubbTg3ByeZFOJBIjVKgeDlC4wJdYdkpL88qEhQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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