SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '849ecd14afd747712a9f96fa07dd46515eca7c80beddbaa7d066f5d4a23612d9' 
  AND token = 'IMQEe7AhuBXr0NDCurfG5sytGrCr0R5nceZdqJpP4mw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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