SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e81c10fd550da3aa64ba6840cd0e1798eff1dccbc4af0efaa5c964465930f517' 
  AND token = 'utp/4aZI1zHwKbjXzGdCdCUvxJ+057z3PTk024fq5nA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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