SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '75697a48dd0283e0b0ecbf79503f939ef762d6e0266e4da42e0ac8c7c778ced9' 
  AND token = 'mnO4jYHpsnZ90BPHXvHJZaAXpJjh3F4wEbB5sPfGBBU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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