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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4dc384eaf1f66e268471e616d053d3735508081a0093d07a38864b4022f8011' 
  AND token = 'oJXUD7REs1ebQlFzv909t/jvJ6J+VMyMQ1M5jOXBY5w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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