SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0ade6ed089987f6814f7bb62c5962e52446ecb627867947c484fdad0f296293' 
  AND token = 'PS/rHq5b3NwF7DyEYMz+wOq3Pgoj+8P6+BRPVdVfDfU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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