SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2948f5bd781ed03911700bec42f3ee736a0f265d10919095866e4addabb96aac' 
  AND token = 'pRHcVHEKlCpYqogW+/h+NgupPHUCCQQsN+ILAUNUKhs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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