SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f3e532284e912ea987e7c6d4182deddf2359abaf4054f620f8572da10fb73f3' 
  AND token = '3jGE7w6HIf/nDNgtVj0Dt6MaH4N6vuZxGhRQzrUI38Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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