SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c837d7b482b830726c48112f1324d0bb87b0f020ad19109614c2a0eaa5c51f24' 
  AND token = 'X44vbF7/i3TJfdgsPMjmgokdsZNunfV1ymrYMGIXRtI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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