SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92b392a3c02b0be190a29645f53f748cf1198e75912f886403a1343a86abf456' 
  AND token = 'Na7qwZd4lH9Dq2qbWLOKsxYH9sZhYh+jx9zVk0MtOfI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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