SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'fb75eed915d7e13f92ca209ddd60fd87151cf64089441c2a17d61249d4538dc4' 
  AND token = 'ALn0Yf8SmKlpgVbTsJXqBXO/giVPM47MC8NovroTA6M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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