SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b2f9ce3f9956d817ed8fb1f0f27f45f1d0afb35e112813d16f68466882ba597e' 
  AND token = '5GnI9/WCV0iqRp3OqwEOgyQub5yGnHv1CGKSTzpi9rY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}