SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2681fd9d4f91296f8c2dfbb7976b56b5d231f251ebd16d4c0b994f2dbe950c34' 
  AND token = '8TsNyBGpBOKF8W4FEZ/fq2MmRX24oYPiHouBJ9VCeWg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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