SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b2cd1aef9eee4eade2c519a15b676950e3207d2d833dc84331039ca857d470f' 
  AND token = '9+gBRN1LKX/HssIIqyyq4JPZ5rxbpzjzolIx6CvJ2Yc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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