SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b74cf939fad1d5d5f1140131444e974afd573466fcdad14027356d65bf47495' 
  AND token = 'Yse5kkqMhzGwtbv13I1ZAN0CAalfir7LOC7hS1YN1VQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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