SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99baf0d3b66ff3b39f890430f1b2ebd386953d70858fa7a2f399c3b42029c66a' 
  AND token = 'Erd4xYTYrPjKtsEJdiVRyBwvxiDaELB2XNVGqSm/FVY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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