SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b5a7ada2c041b630c5a4fc179a8aee8fa6fe68455846fd0ffeb39dfa1e69dc5a' 
  AND token = 'TRNvuG3uWAbA7iV05fO60GLELWKPabREmX7FWkEia20=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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