SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55efedee935aa82f42b7dbc3f285d7189adde086deabc09119151b56c2ea8636' 
  AND token = 'B0Q7PqfSYVvvgPZrb+kNKn2g1NmbhgZR8hcEXI4jths=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00059

JSON explain

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