SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'ac6d12f1ca6f77d02c187357d6e442ea053d88c656d77a5204b1d29e9da34dc9' 
  AND token = 'w7QP3nlXIaj5g31DuVz9ZqdJroIMxQMBjE1TXUswHrg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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