SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1efee4d34f57d01db1906d7b847a5290536e536acf4f71ebf5a38fd98c1d5cb5' 
  AND token = 'SBPPefoSNKOVzSciuW8K2YqhymBf+AWbrcnEKDckvIU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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