SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2fd0f06a18150322d6da23f4c340242d3e5bd8a15ce77eca3e4ea1f7dffca9a6' 
  AND token = 'g20gXRS2uCnQbIxmdbU1D5/es7phXxv+W7pp1jpE1Fg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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