SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f7028d3858acd2db47b14d3cbc77ed51bbb2f769a6093c65d2e982d2b096a18' 
  AND token = 'fCZfKV0h0b+liTzzyhSBzvupxDVL66lNpYCbQySYO7A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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