SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af0ea42ddc6acffb751dba8ea3f2742ec5921b52d51338626a112055bcca56fb' 
  AND token = 'dN4An4G75kRdytXPKRqEBzWRRmNzILqEoNhxRE4SRbU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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