SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd3c1a5c063a9716ccb9c68549ec98a0b326e37f89e2b6970e65efb8cd9ca6b73' 
  AND token = 'dUK0/X2phqBzja4WI0a28kXwJ01jzpwTGg/56PeoOwM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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