SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0eeed4b1627f9a2c49c81f4246f64ab696833ad704c62aee6862435b3631998' 
  AND token = '6NDfucVy/aoNIvjpFGLCchX5vjX5HDOQBMRAUmoqJQs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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