SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b1f7189f68132c1315f5d65a5f223c98fdb493ba1ad6b7f5cfef4dec7efc6e3' 
  AND token = 'zLLOAUvkbOwBA7XE4QOHwfJszYfYaoTPAVdoXx0HLdw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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