SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f70fa296d40a2734a145092a1c8e635e8f9671c9e37ce9997355217ef52db8e5' 
  AND token = 'OlIMNbKj/tnWnTuH6SXHsgY5vXtm3e7LsY8C6KBwAzw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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