SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f78f2dd7e470a62bc8759dc9f4b75448c3da9fbeb5b45e491373460266515502' 
  AND token = 'sHBDT/VoRLhIRVH4irVXsq87a2DZLLj5iJW1h2BVQLE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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