SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e2d51784836a826dbb8f5bd69ab92f5a61a1d8530cfd131d3c39c2aa2cccb182' 
  AND token = '7GfBgtPym7/wx5hOpWj+xrvpwv0ExL7ZCXp1eHf7OLw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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