SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8eaf8becf1155d76ec4e4a1c984719be6d0b5081b1bf297016873ef40efa735d' 
  AND token = 'q7MMiXejVvDXgCkQB7nJ2BBu4kIwXx7KZbBingI+Z/o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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