SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9804539e6bee38d3cd3201e02f9b8df576ab2d203a1e036503cc468e9a7fc6b' 
  AND token = '3BdwozuZp/PsLyRwY7vh/HObfDli1ZB2VFCxYxd8cRk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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