SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd268a0271923183e9f8e194f957b0fd3af6d3929c2ba933e63b2e99c186dc9f8' 
  AND token = 'EBMyhNV/gk5+urD/n/p95gw55+46pQYw3doyqIzYLXM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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