SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '724724c55933e8c4e2882aa6bb1feab9561d993060fc5bfe25a50f3f522ed199' 
  AND token = '3aJu92/1P+/YCl4gqgA/gjDtrm6SsBFyGc+wWPV4wXI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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