SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '268411539d4b7436526a61c4d60fcd1546f01c588eea9bcb08e9a9c289b80a21' 
  AND token = 'eut0qgeyPRFHFTZFGlpQLibYqdJso/D4goWFtthzqGw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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