SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3aaa7e95bfa205f03dc68056c2380f2fe22684e527debaf9ad0e62df3c9fd0b7' 
  AND token = '1oeOQaFDySQAlEMZQlu3UEKA/IbPuUNiX1+FSoiQLxo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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