SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f73c635aae7ca70ea072cc5a4230fa2ac61f0bb750388f92da84b0fd0d83385' 
  AND token = 'Nt7sbWDTS74ZKb3++04D5LURNP+YBIof3MuKGPp/ptg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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