SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b91c480c61f07b09ffd614e604ae93dfc625d01636473252fa1c2af48dcdd5d0' 
  AND token = 'GYpJ4Oe3t7TlMDGwCS4PlQpEFCJ4Sw5qjnbIIuBY15k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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