SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4d1f51e6eaa9619a58a45561f7adb8462941ec530111be8f1203678e835d8f5' 
  AND token = 'Vhaz/49B1xWHZm7VmJQDkuTbmYCzjqaao9xg3qw3cZo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}