SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a11e51d23a765b3d3a47961d18f283d703b2dcca25806a4393efafb744a2f95a' 
  AND token = 'YCQIzuapA45GpgVTRBQrJfNtb1zKspFr6AswHgyXjxQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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