SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b84eccbec44a2ac6c7534ab3740aca4cefc163c90c08257249339af05f7a5774' 
  AND token = '6ZLKsdlQL4BnT5HQ0zrm+N6VOOL8xU1JGkCqI2ph6rg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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