SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f67b46a68f4bd68b99bec3228cedce71ebf064fb7da3857ef1065fc7d723fa76' 
  AND token = '/QFSpdT6dfoCSFASyalDyP6JEyOV2T7kAf2XJ6crCfE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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