SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99a182089d021c7b1117586a41892623131755ed069d45e6f0ebd2373d9326fa' 
  AND token = 'xJHNJMuK3c1zl30UZaeSH+iX0WIpk8EkKMsal/PQ/d4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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