SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a2ed1337011fbfda1326332306bc4eff569532bfdc3ed371029f9fd6d7bf2b8' 
  AND token = 'XcUdkd+JxIpQYK10lWZUaryiYmmRgMJyQamkPCdZlnc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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