SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18621693a5c5a877c68a717bdbccbd5bc6b6f2912f1f23729df2045266e2526d' 
  AND token = 'd7xXF4DF8BRl9j/qTEMmWafzvDfCHCZv8RPN8Y/MhEs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00050

JSON explain

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