SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff0c371229fe54b41805d8777ff35be644f2b5f0013025268ea36d5565a52279' 
  AND token = 'cakS8c+Y3e2pPDqRJz4GYeJnKDaGsd0UjNMTcHN5l54=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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