SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '5709e0a41eb48396977164cff068a3c2c64a09fece0508974fcaefd915e4ce3c' 
  AND token = 'fY+klExemzCscYL3cORPzPCXMTIKFNs+riW6jcI32iA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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