SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b982284958bd43705d5035aee9d79387d1bb8112eab55d21b527bfba8928c84f' 
  AND token = 'tPM6ItSBxrai+xN4nC3fGwxsBF+2+1uUMhwd+sUXmT4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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