SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f19cf8ce92e20aa7865fd4da7969fb820417880aa597182e8a1f985b975cb2b6' 
  AND token = 'I68Q3xLRbZ7A4KVjrlmEOoZFIQhEqA1phxYvpU8AJIw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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