SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '16f5dde512c74876e473476e9948310547a2022150af82be6ac5ce20249827d0' 
  AND token = '/OQg8qZhYP+EeJymop+36ImP401++xEf/dBJ8euAuQY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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