SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af817bd271cdb70f6402d2f64b8c4a4777548a7b0ef6b605996670d77a092705' 
  AND token = 'DyB/ZMHmpAVW+mK7xyH6Y8APhzIlQpkKwv1V7t33i2k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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