SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '336a94ddf47cd13a58b747dd150b0d2af1b76327aef8072a268ada8fb7fb9a55' 
  AND token = 'GqIdBPiJl8Ajv0CtjV7J0m9h10XraT2gKqUUBHIqtuk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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