SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30247ac458a9a9ebb5d2646abc6523bb7323fb9c2a891ace53bb64f723b6943a' 
  AND token = 'LdmBm6HXH2lIj2JKF3CRGz+IxsOxgPHrf4kllvYpYxE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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