SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b43497e142a32467ef0409422463580eed2386f4242cf544be830d3b00765e4' 
  AND token = 'Lavs5C9fi26aJaGLylKcpN/xfXOr16R5/O3jj3NA4UE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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