SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '12c98dc2e0818c2a8cf66b5bb1ef5b0e688f8024bf592ff9ee0d2da908a742a2' 
  AND token = 'OiOLTrW9erdoKDZwfxw5O7EmwF872MHTHyBR7yJMiHw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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