SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82d3536cebb41f712f6c2b34a78782ec9d1b812e81a45d8563bff8019bca0efc' 
  AND token = 'MgV9CZvjUcz+xuS7p0JIIbasoCIK3vw4Q+MK7USieoo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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