SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3e42dd967f1fc6e83ab9a8424f325cd1fa1ccd0663e29d3388de528a6ae597e' 
  AND token = 'G4rBMNcqt4VfPHY2YPZ1SmAMSIpPwzZZLRGIGEq/Wjo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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