SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f42a0bb57cf8e58171174f2bbcdd6723b18b67862dacecb4dcbf7e703fd6a7a8' 
  AND token = 'jqXwsDPsXmY5HLQb/wZ4J9z24/krC+7d7FAVomgqvIU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}