SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b27181bb02636bc4602a67d927fe4e8a8debd525975e72d715a1676b47d429f3' 
  AND token = 'eOOBrYeqPI3xlk+dv+ZVLsn+JgmOIKpFyngN/IwOuE8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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