SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5fb22f7039a95878c13df234c2d63d5de325361a17a882934857cbce6760195f' 
  AND token = 'yPivK9g//wJiAhmVXECTjfKkw1gNBfjiIP71lElQmC4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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