SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03c9694c6810756628d87f761a3739e0a1a1ccbaf8d5928acecf010ca396e0fb' 
  AND token = 'v0rGbC2YeuAl30BTMqsGgVK5OWDbCJKy7dH1qHUykb0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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