SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54633bc8b5b93be252193ff64ef63e0f9d8049e303c8d6f1969d154db562d530' 
  AND token = 'lUcDNLuStfnDHp31Su3sMgNAooreMfiNg7RVP3ZXr+E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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