SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a10c499ff25f977b4ae80dfe63016938e19313bfc540e683791cfdb0798264f' 
  AND token = 'VxEbNmdVEEzZiTviZbLSI2mmNX7sSmaRPB/TpR4NQIQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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