SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '498bae55b1b684e88475c1d5cf6a1e48c2609629cc4fcc39c857c68e134b63c3' 
  AND token = 'hBQaDGedQg3pmgB1cfV2kosB7AyJOV5nQGnV4eCDi0A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}