SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82e39a40f3b5a769b917c788b92d74c600c174d0ecf87fa2ccdba9e8a3efa8b5' 
  AND token = 'mjVeR9sxwBJyZupBweOGualVVddQkium3DOiNhThraI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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