SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a2d229bc0524809e81ecb86287e5bc471a78dbcb789edc8c5ea8cc327148800a' 
  AND token = 'CdVbx/C2qcg8xfWubdsvuzpPiq028yvbLkHx/UkBs/s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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