SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96e21a6237c83b3af80cc92c9276b09d18d31cac63724bc2e8145634b17ecbf8' 
  AND token = 'IMVYUq1tD5ROc95k2nZy7dFt7xInd9EbZPc+k7F6qTE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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