SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'c1fda21725bbce706ef887960a42b706f874348d5792e8c408e14caa7b4220aa' 
  AND token = 'vAAbX/GEwfX98bvSXD9JqUwrKu/6GGryiJVHVKYoRIc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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