SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85b1fc1360123d15040deec81bac2d03a1d9b9e34e4af38a163a847ed3f56bd6' 
  AND token = 'S7Kf92GdGSKGt8NR5VyBevLGqIIGfGWagQx3jG4FCk8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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