SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c985c1a12777e805a39798d9c77f22c01d837869f54fe69cc8aa7032525ed2b' 
  AND token = 'kMLoxznz8KNVJFWa+q15XZhx/7+m0bY42RQbazq4g9M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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