SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b37c0aece7b0e278fd701b6ad447d388212877dc2da8265ea07380e81719c5e8' 
  AND token = '+BG7tbPZH/Uv4WtCANFJQLvwyp/gApmYDddfly5MLiE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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