SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16c32eb1d7c49cf9aeecd2ea7639ade5ea26e7e239fb6b55d33d5938b9899cd0' 
  AND token = '58dPJXFT/pE9ZJJe+kph4P7r4SJmlVBXG9xCiX2OTYU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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