SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76fde08c4a11c6d4722d5a5f5383c6e2f0cbfb1ebd80d131bce1a6604ff81608' 
  AND token = 'QEobyCdGQdeWZEnWJkycyHEhcUhpHNYVAAnJBsI2huQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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