SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0ad880be1c3534692fd0fb1f746673498adb93cc8c2aa08b637dfa119974df44' 
  AND token = 'SpJPEWyst+dKPnymr9zN7gkmxZ7OppFMnIDWd6cKUaA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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