SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e8b8e7dd17402b2ccf1d32749396627591f10b5959543778b32f02ab9351510' 
  AND token = 'BVxeQZ7n8G49SYMuDEyM1SHDxZUlS2Rm42acQkmHfJI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

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