SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3596b8327e90ed380239ab5eee997ea9e8742c3db9a81b28932656e92bbb9e0e' 
  AND token = '4nZauryrmMuNEDOcIzeRktzl+L5Zbrlhi0NsOgzT7qM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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