SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ba64398e694af9e29eaf674e01f66d76468b5209e8c2b348a893e88566269c0' 
  AND token = 'svPLMBZ4IRmp5CpWh5ZlY+f2blA+HlQ9ijqlgPQazjk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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