SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f71b1fa071bef453199a88aa98e95323bd6ea6bad96cdfbcbd81746e0b64b439' 
  AND token = 'yzEwRJejTbYNoC/PvVQ+OwlquaiPdTh3wB8VIxOyQXA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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