SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '9111ff5fbb66d004658879c2e274130b85f109d6920a1818f43b4ec4bf8a79f2' 
  AND token = '/GxAzLA4X+IO2dlydOY5/nXPcdKx96LGpFTriLuqYR8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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