SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47200cbc06d689551851b5dd511e02e2d572311e7bcc25bf2bb2753c425ab3aa' 
  AND token = '2FICJv+RBzfvGSp4YmSWjGo2CaSJaw1296iCD01LOK8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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