SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '249cfd1afcdc43b839e07774cfc7bf35173896f56685ac7740512f82ad426ec9' 
  AND token = '5Y59LqxTU2rAOdzLKSBaejjBUuYpCSzuHpzpKaKRT/4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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