SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c79f6a192035795a1dbc0bf88d696ac92f9288edb09b212bb00e5d231f9b318' 
  AND token = 'Pv7JwP6UXLfoY3QFwX+riPS9CZQABhFnIHSr+341i7g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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