SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0ff75418c59d77c17bc661e4956c1f844ebb9cef3dc2bb20a588c7ff2c3169c' 
  AND token = 'olBHfTvYKU28HSCwNzznGLL6z9dxKBATw5/JBR//oaY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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