SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1319521fe1704cd2e43677bd2831fbc8d88ab511266cccf09672b9d196447310' 
  AND token = 'EK3jQQuDuTFagtoc3UZ6EsA7zygJpJJWQ9oiaXODYZw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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