SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f0b8f55787f6c21f913cf8c38a1fce831b7fa00cc04ef3e1e93d4869949b18d' 
  AND token = 'C6g/Jl2eB/ruhGFDiw9BynVz5rHUOasr2hDI7/Zpi7Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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