SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40f719d2515bfe7371947f256a63aa01f83a5e516cec693cbe60dbbfe53d83df' 
  AND token = 'pVPAmo9zpQInefHatipx2KclbUHgL4+vjG3YnN/gfgI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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