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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ae167718f9e699df926d4e5b1540b36cd0f877aa9b0d26d2cfa21a9edd0e1d0' 
  AND token = 'yRM6cKzNsFNxnqDQlzN+vU5ZDwqtNAtsmRj0nHKc8j4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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