SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '364955913125b0a46c63585a885201ba5215ea70087707a57d8162c62b98bcf1' 
  AND token = '7w+Oj4B4UXpqfldDhTMvHyXPSNTTL0zBg4pTbpVfCpM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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