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SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b9d2bd076e4111fdc3ec9804bd73cc50afc581aa8a6dd1ed4dffd0778fffcd52' 
  AND token = 'UG2cSXDjyE01pPkjMQjgUjNmfi1kPQ941ARSitjcr1k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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