SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'efe374a3eb6657e6a24e505d92852c07ff1d0f42567b442ddcd58d0720840ae9' 
  AND token = '8fIAENi/HZat5KrpfdgUVa80lkXUZOTYcYjKDqhikgw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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