SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c01873691e66b90892a352d53701379c99971fd18405df9f7779d42f8293c71' 
  AND token = 'MgU8L2bIywxhF8jBSjmLl4scTdjRj+ZqEFe8rd/q16Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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