SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73ce30ed5a7b56ec196b4687122e7491ce37b482c7c3cf44e70d1f6f766e3662' 
  AND token = 'rJpQNBcYa66OlEiQEsueIRl8KSCNhs/5OXGmqv6MFgQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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