SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3e0c308503b867bde6353d3ebd8bb479794b6ca3bc0e5c0753ef59a93a1915b' 
  AND token = '6FJBOPHH2vXRFWcP83siHwWTAPvIWsNhnEq9jRQDMfY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}